The present invention relates to security systems for shipping containers, boxes, cartons and the like and, more particularly, to such security systems that can detect tampering with, or breaches in, surfaces of such containers or nuclear radiation from materials placed in the containers.
Cargo is often shipped in standardized containers, such as those used on trucks, trains, ships and aircraft. Smaller units of cargo are typically shipped in cardboard boxes and the like. It is often difficult or impossible to adequately guard these containers and boxes while they are in transit, such as on the high seas. In addition, some shipments originate in countries where port or rail yard security may not be adequate. Consequently, these containers and boxes are subject to tampering by thieves, smugglers, terrorists, and other unscrupulous people. A breached container can, for example, be looted or surreptitiously loaded with contraband, such as illegal drugs, weapons, explosives, contaminants or a weapon of mass destruction, such as a nuclear weapon or a radiological weapon, with catastrophic results. Alternatively, a nuclear or radiological weapon can be loaded by a rogue state or terrorist organization into such a container for shipment without necessarily breaching the container.
Such breaches and weapons are difficult to detect. The sheer number of containers and boxes being shipped every day makes it difficult to adequately inspect each one. Even a visual inspection of the exterior of a container is unlikely to reveal a breach. Shipping containers are subject to rough handling by cranes and other heavy equipment. Many of them have been damaged multiple times in the natural course of business and subsequently patched to extend their useful lives. Thus, upon inspection, a surreptitiously breached and patched container is likely to appear unremarkable. Furthermore, many security professionals would prefer to detect breached containers and radioactive cargoes prior to the containers entering a port and possibly preventing such containers from ever entering the port. The current method of placing a seal across the locking mechanism of a container door is of limited value, whether there is a physical breach of the container or not, because the nuclear or radiological weapon could be loaded by terrorist as legitimate cargo. For example, the terrorists could circumvent or corrupt inventory controls and cargo manifest delivery systems using unscrupulous confederates. A single breach or circumvention of a cargo delivery system by whatever means can have catastrophic consequences.
There is a need for systems that can detect the secreting of illicit radioactive materials, nuclear bombs, and radiological weapons into shipping containers and other enclosures. This is a matter of great concern to the national security of many countries. In particular because of the rapid advance in methodologies, since 1945, to make different kinds of nuclear weapons, it is now possible that terrorists or rogue nations could make less than perfect weapons that nations with high standard of technological achievement have obtained. Specifically, because a plutonium weapon threat may also be materialized on a non-sophisticated basis, covering a spectrum of barely functioning weapons, such as the North Korean “fizzle bomb test” or the use of reactor grade plutonium, it is apparent that even unsophisticated weapons in enemy hands can create a crude but effective nuclear threat. The prognosis long term for nuclear terrorism is even more alarming. The ability to create a rudimentary fission bomb with as little energy release as ⅓ kiloton, has the capacity to trigger a hydrogen bomb. Hence, the need for a detection system that has the ability to detect and analyze a wide variety of constituent isotopes that may be used to make a less than perfect weapons grade plutonium bomb which could be used to trigger a hydrogen bomb.
The inspection of huge numbers of shipping containers with expensive fixed and portable multifunctional radiation detection systems is not reliable, practical, nor even capable of detection of low level radiation emissions, such as emitted by plutonium or highly enriched uranium. These current detection systems are not capable of inspecting large numbers of containers from either a necessary “detection time of measurement” or manpower perspective, let alone meeting government objectives of inspecting 100% of all containers entering the country. The current number of containers inspected is only approximately 4% with a significant number of false positive alarms. There is a need for a practical solution to automating a 100% inspection process and ensuring that once a container is sealed at the start of its transit, it arrives at its destination in the same sealed condition, while simultaneously during its transit being continuously monitored for any secreted presence of illicit radioactive material.
The problem confronting persons responsible for taking measurements for detecting the presence of radioactive materials, such as customs officers is extremely challenging. In addition to practical time limits of taking radiation measurements because of the requirement not to unduly impede the economic flow of containerized goods, there is the lack of a readily identifiable solid angle of emission from a secreted weapon buried somewhere within the container under inspection for the presence of a radiation source. Because the emitted radiation from a weapon such as a plutonium or uranium bomb is very low, as these elements have long half-lives, are essentially self-shielding, and may be encased in a protective lead shield, passive detection of such emitted radiation is very difficult. The conventional approach of random wanding of suspected containers by portable hand instruments in an attempt to indicate a possible radiation source is not effective especially because of material background radiation and radiation from legitimate sources which have attendant low level radiation emissions. The key to using current detection techniques whether in fixed portal systems or hand held portable instruments is the necessity to employ very sophisticated mathematical processing algorithms to detect a weak weapon radiation signal out of natural background radiation or certain types of legitimate cargo materials which emit radiation. This is an attempt to compensate for a lack of adequate time of measurement. Alternate inspection regimes, such as active scanning with gamma rays or x-rays have proved ineffective for a variety of reasons, and are considered by many skilled in the art of security matters to be downright dangerous. A terrorist could easily configure a crystal radiation detection circuit as a booby trap trigger to detonate a nuclear or radiological weapon in a port as soon as it receives an active scan by a gamma ray or x-ray machine. According to many studies, such as by the GAO (Homeland Security Committee, House of Representatives—Mar. 14, 2007), on the efficacy of these techniques, they are not capable of performing to the designated detection performance goals of the federal government. Compounding the problem of insufficient measurement time for detecting weak radiation signals buried in background radiation is a lack of knowledge beforehand exactly where the solid angle of emission lies.
It is known that optical fibers used for communication systems and the like can be sensitive to radiation in terms of adversely affecting the qualitative and quantitative transmission of light in the optical fiber. Such fibers are usually designed or selected to minimize the sensitivity of the fiber to impinging radiation, a process called “hardening”. Such fibers are also often designed or selected to recover from radiation induced darkening so that the fibers can remain useable for the intended purpose of transmitting light signals. Radiation dosimeters are also known for detecting nuclear radiation and such dosimeters are usually recyclable and reusable by recovering from the affects of received radiation.